import java.util.Arrays;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        int n = in.nextInt();
        String s = in.next();
        char[] arr = s.toCharArray();
        int x = 1;
        int tmp = 'a' - 'A';
        for (int i = 0; i < n; i++) {
            if (i + x < n && (arr[i + x] >= 'A' && arr[i + x] <= 'Z')) {
                arr[i + x] += tmp;
                x++;
                if (arr[i] >= 'a' && arr[i] <= 'z') {
                    arr[i] -= tmp;
                }
            }
        }
        for (int i = 0; i < n; i++) {
            System.out.print(arr[i]);
        }
    }
}